Concept:Gregarious animals are members of the same species that gather and move together in a group.
Explanation:The term gregarious describes social grouping behaviour in animals.
Such animals form herds, flocks, or schools made up of individuals of the same species.
They move, feed, or rest together as a single coordinated group.
Therefore, an animal is said to be gregarious when animals of the same species are seen moving together in a group.
This condition is described exactly by option C.
Option A refers to surviving harsh cold conditions, which is not a type of group behaviour.
Option B refers to passing information between individuals, which describes communication.
Option D refers to alarm signals that trigger protective responses, which is a social reaction and not the actual meaning of gregarious.
Answer:C. they are of the same species moving together in a group.